Field of the Invention
The present invention relates to a structure and a method for mounting a device which measures physical amounts on the outside of an aircraft or other devices onto an airframe.
Description of the Related Art
In a flight test of an aircraft, a measuring device which measures a water content in the atmosphere is used in order to know the state of ice accretion on the airframe (e.g., National Publication of International Patent Application No. 2007-521463).
The measuring device is fixed on an arm which is provided on the airframe and protrudes to the outside of the aircraft. A large aerodynamic load applied to the measuring device and the arm acts on a part of the airframe which supports the arm.
The airframe of an aircraft is required to achieve necessary strength and rigidity while being lightweight. If the strength and rigidity of structural members (frames, skins, stringers, etc.) of the airframe are increased, the weight of the airframe increases, which affects the flight performance and the fuel efficiency. For this reason, the rigidity of structural members of an airframe is increased only to such a level that they can bear bending applied during flight or a pressure difference between the inside and the outside of the aircraft, and not to such a level that they can bear a large load acting on the airframe due to installation of a measuring device outside the aircraft.
Therefore, to conduct a flight test, it is necessary to modify (alter, reinforce) a part of a manufactured airframe supporting the arm on which a measuring device is fixed. The modification is a large-scale work involving destroying and cutting away a part of the airframe structure and constructing an arm support part in the cutaway part.
When measurement with the measuring device is completed, it is necessary to remove the measuring device and the arm and restore the airframe to its original state. The arm is firmly fixed on the airframe while maintaining the airtightness inside the aircraft, and therefore structurally cannot be removed easily. After the arm is removed, the large-scale work of restoring the modified part, including the airframe structure, to its original state has to be carried out.
Thus, mounting a measuring device or other devices to be installed outside the aircraft onto the airframe requires a huge amount of time and effort as well as a high cost for modification of the airframe and restoration of the modified part.
In view of this, the present invention aims to provide a structure and a method which can reduce the scale of modification of the airframe of an aircraft and allow a device to be installed outside the aircraft to be easily mounted onto the airframe.